Wavelength multiplexed optical indication technology is currently used in high-speed high-capacity optical networks to support high-level data communication firms. Advances are being made in deployment of ROADM (Reconfigurable Optical Add Drop Multiplexer) devices that have reconfigurable add and drop functions. The ROADM device is structured from, primarily, a wavelength selective switch (sometimes termed a “WSS”), a wavelength blocker (sometimes termed a “WB”), and the like, to be an optical node device that includes optical filtering functions, optical attenuation functions, and optical switching functions. In order to achieve the ROADM device, the wavelength selective switch must switch light of an arbitrary wavelength in an arbitrary direction. In the wavelength selective switch, an optical beam deflecting element that selects a wavelength and deflects the optical beam to a desired output port is used. In the wavelength blocker device, an optical beam deflecting element is used in order to select a wavelength and either output or not output the optical beam to a desired output port. Patent Citations 1 and 2 propose the use of mechanical dislocation of a MEMS (Micro-Electro-Mechanical System) mirror array as the optical beam deflecting element. Spatial light modulators (sometimes termed “SLMs”) are also known as optical beam deflecting elements. Of these, there are liquid crystal spatial light modulating elements known as LCOS (Liquid Crystal On Silicon) elements that use CMOS technology. Patent Citations 3, 4, and 5 propose the use of LCOS (Liquid Crystal On Silicon) elements.
A control method wherein a phase diffraction grating (Optical Phased Array, sometimes termed “OPA”) is formed through a phase modulating function and the diffraction phenomenon is used, and a method wherein the amplitude is controlled through rotation of polarization are well-known As methods for controlling liquid crystal spatial light modulating elements.